Land of opportunity for Southern Europeans? Germany.

After two days of sightseeing and night clubs around Berlin, Iker Martinez arrives at his German-language school Monday morning to find the steepest cover charge yet.

"For September," he says, forking over 222 euros – about $280.

Moments later in class, he jots down the vocabulary his teacher scribbled on the whiteboard – the German words for "first," "then," "later," and "last." Then, studying a jumble of photos of a factory in his textbook, he racks his brain over how to describe the production best.

"So," the teacher says, regarding Mr. Martinez and his seven classmates, three of whom have also just arrived from southern Europe. "How do you put a car together?"

Martinez can go into depth about that. In July, the 28-year-old mechanical engineer left San Sebastian, Spain, to join the growing wave of young workers fleeing the eurozone’s crisis countries for better prospects in Europe’s largest economy.

In theory, the match-up is a cinch: In Spain and Greece, the unemployment rate is nearly 25 percent, and more than double that for people under 25. The job outlook has also darkened in Portugal, Ireland, and parts of Italy. Meanwhile, large swaths of Germany have companies that are scrambling to fill open engineering and technical positions.

In practice, though, it's more complex. These days, few Europeans grow up with a solid grasp of German, which is still necessary to handle many of the job responsibilities here. The work is also scattered across this Montana-sized country, often far from major cities, forcing the likes of Martinez to make a choice: Live in Berlin – where the rent is cheap, the immigrant network is tight, the entertainment options are endless, but the unemployment rate of 12.3 percent is Germany’s highest – or look for work in another area of Germany where adjustment may be much more difficult but the jobs are more plentiful.

Catalan in Deutschland

On a cobbled crossing in Berlin's trendy Neukölln neighborhood, the Spanish pub Gastón offers a window into this tension.

Skateboarding into work on a Saturday afternoon, owner Bruno Fraysse greets his handful of staff and customers in a mix of Spanish, English, and German. His girlfriend, a Hamburg native, slumps at the bar, lazily swiping her iPad. In the cramped kitchen, young cook Gabriel Sergent, a trained photographer who left Andalusia this summer, is frying fish. A sign on the wall informs: "Every Sunday, Paella!!!"

“When I arrived, it was impossible to hear Spanish on the streets,” says Mr. Fraysse, a firecracker of a figure, whose arms, legs, and chest are covered in tattoos. He moved here from Salou, just outside of Barcelona, in 2006. “Now I can hear Catalan!”

His observation is on point. In May, roughly 46,000 Spaniards had registered jobs in Germany, an 11.5-percent increase over the previous spring, the Federal Employment Agency reported. That trend also emerged among Greeks (up 9.8 percent, to 117,700), Italians (up 4.2 percent, to 232,800), and Portuguese (up 5.9 percent, to 55,600). The statistics, which don’t include people earning money under the table or looking for work, suggest that this is the biggest influx of southern Europeans to Germany in decades.

For Spaniards, a group that lacks a big toehold elsewhere in the country, the destination is usually the capital.

"Back home, people say, 'Germans have Majorca, and now we have Berlin,'" says Mr. Sergent, the cook, referring to the Spanish island famously flocked by German tourists. "I think this is the most happy and easy city to live in Europe. The only thing I do not like is the weather."

But the growing fraternity of immigrants has its drawbacks.

Behind the bar is Lena Campbell, who studied economics at university back home in Ireland. Unable to find work after graduating, she settled where the living looked good – and in one sense, it has been. Four years on, the farthest she’s explored in Germany is Potsdam, 15 miles to the southwest.

"I work here, I drink here, I party here, I live here," she says. But the pickings for jobs are slim and the candidates numerous. "We like to have competitions to see who's the most overqualified for their job."

Go west (or south), young man

Elsewhere in Germany, immigrants don't face that kind of competition. Caught between an aging workforce and a generation of young adults increasingly heading to university instead of the trades, the country is staring down a workforce shortage that some consider as big a future problem as rescuing the euro.

In June, Germany was operating with about 110,000 unfilled engineering spots, a rate that costs the country up to $10 billion a year, the Cologne Institute for Economic Research reported. More than half the open spots are in the Ruhr Valley and the southern states of Baden-Württemberg and Bavaria – where the unemployment rate currently hovers around 4 percent. By contrast, in Berlin and the surrounding state of Brandenburg, there are fewer than 4,000 unfilled engineering spots.

Fearing a loss of competitive edge, businesses from the Black Forest to the North Sea coast are actively recruiting southern European talent. Last December, firms in the Stuttgart area invited 100 unemployed Spanish engineers to visit – and reportedly about 30 of them stayed. Months later, the Baden-Württemberg towns of Villingen-Schwenningen and Schwäbisch Hall held similar programs.

In June, Wolfgang Rücker, the CEO of Rücker Engineering & Design, in Wiesbaden, outlined his firm’s goal of bringing in 400 southern European engineers. He challenged politicians to provide a mix of “practical, conceptual, and financial help” in luring talent. He said the government could subsidize German courses and job training, and even connect new arrivals with apartments and homes.

That surely would help the region of Emsland, bordering The Netherlands and North Sea, 300 miles west of Berlin. A recent study concluded that, if nothing changes, the area will lack 25,000 workers by 2025. This spring, the group "Job Motor Northwest" recruited 66 Spaniards, aged 19 to 25, to apply for three-year apprenticeships there. While 15 visited, only five elected to stay, a spokesman says, with the 10 who didn't citing the region’s small size and remoteness, along with the program’s length (such apprenticeships in Spain are only two years).

These days, the five young Spaniards train three days a week as mechanics, programmers, and electricians. They also spend three days in a German classroom.

"They’re gutsy. They sit together in the afternoon, trying to learn our language,” says spokesman Jens Stagnet, who thinks Job Motor Northwest has managed to sharpen its target group. "Next year, we hope to secure 15 to 30 Spaniards. Preferably 30.”

Driving business

Back in Berlin, at least 30 Spaniards have filed into Gastón by Saturday evening, filling the tables along the sidewalk and crowding the bar.

Fraysse expects more of them. In a few weeks, he’ll open a second Spanish pub, and he has no plans of returning to Catalonia. "No way," he says. "I have ambitions."

That said, he retains a hint of awe for one Spaniard who recently got away. The woman, who has an industrial-design degree, grew so tired of tending bar, he says, that she moved 400 miles south to Stuttgart – without a job.

"But within months," he states, "she’s working at Mercedes."